Pyrene is a polycyclic aromatic compound consisting of four benzene rings fused together. Pyrene exhibits high quantum yield, good photostability, and long fluorescence lifetime. Pyrene and its derivatives are often used to make fluorescent dyes, biological probes, sensors, photoelectronic devices, and press-sensitive materials.
Polypyrenes have longer π-conjugation chains than pyrene monomers, and are expected to possess better fluorescence, electroluminescence and thermostability. Recently, oligopyrene has been synthesized by an electrochemical method, and it is found that oligopyrene formed by α,α-coupling of pyrene rings can emit about 9 times stronger and more unitarily colored fluorescence than the pyrene monomers. However, oligopyrene shows dissatisfactory solubility and processibility. In addition, the electrochemical method for synthesizing oligopyrene is expensive and has low production yield and thus not suitable for large-scale manufacture.
Pyrrole is a heterocyclic aromatic compound with a five-membered ring. Polypyrrole has high thermal stability and excellent electrical conducting activity. Pyrrole may be used as a material for electrochromic devices, organic transistor suppercapacitors, chemical sensors and biosensors.